Blood urea content for evaluating dietary protein quality

The protein quality of broad beans was evaluated by using three different methods: the net protein ratio (NPR), the net protein utilization (NPU) and the relative protein value (RPV). Casein was used as a reference protein. The relationship between the values obtained on rats by each method and serum urea concentrations were examined. Serum urea concentration increased by increasing the dietary protein content. It showed a positive correlation of 0.70 and 0.60 for broad beans and casein respectively. NPR values increased by decreasing the level of dietary protein. There was no relationship between the NPR and the serum urea contents in animals fed the casein and broad bean diets. The NPU values indicated that protein utilization was greatest at low dietary protein levels and decreases by increasing the protein content of diet. Serum urea concentration showed an inverse proportion with the NPU values. This was demonstrated by correlations of ?0.67 and ?0.75 for broad beans and casein respectively. The highest RPV for broad beans was obtained by using the change in body water and the lowest by using the change in body nitrogen as a response parameter. An inverse relationship exists between serum urea concentration and the RPV for broad beans.     

Nutritive value of some common Egyptian meals

The protein quality of two common Egyptian meals namely lentils and "Koshari" was evaluated on rats by utilizing the net protein ratio (NPR), the relative protein value (RPV) and the serum urea content methods. Casein was used as a reference protein. The macro nutrient contents of the two meals are almost similar. The NPR is higher with low dietary protein level. The estimated RNV of the "Koshari" was higher than that of lentils. Lower serum urea levels were found with the "Koshari" than with lentils meal indicating its better protein quality. This is most probably due to the effect of amino acid supplementation of cereals and legumes. Results obtained are in favour of utilizing the serum urea content method as a simple and reliable one for evaluating protein quality since a negative relationship exists between blood urea content and the biological value of dietary protein. Its validity in estimating dietary protein quality in man need to be investigated.     

Physicochemical and Functional Properties of Winged Bean Flour and Isolate Compared with Soy Isolate

The proximate composition, amino acid profile and functional properties of isolated winged bean proteins were determined and compared with soy protein isolate. Winged bean protein extracted at pH 10 and pH 12 had protein contents of about 90% and 80%, respectively. Alkali extraction of winged bean proteins at pH 10 and pH 12 did not affect the amino acid distribution of the isolated proteins. Oil and water absorption, emulsion, and foaming properties of winged bean isolated compared favorably with soy isolate. Least gelation concentration for winged bean isolate was 18% compared to 14% for soy isolate. Thus, winged bean protein isolate with its high protein content, high lysine and other essential amino acid content and good functionality has a good potential as an ingredient in food products.     

蛋白质和淀粉对肉制品品质影响的研究

选取了三种蛋白(谷朊粉、花生分离蛋白和大豆分离蛋白)和三种淀粉(玉米淀粉、红薯淀粉和绿豆淀粉)作为肉制品的脂肪模拟品,经比较分析可知,大豆分离蛋白和绿豆淀粉均为肉制品的最佳脂肪模拟品.通过单因素试验和正交试验,结果表明,当大豆分离蛋白和绿豆淀粉的比例为1:4,添加量为15%(占鲜肉质量分数),水分添加量为20%时,肉制...     

SINGLE-SCREW EXTRUSION OF PORK AND SOY FLOUR BLEND

This study examined the rheological properties of defatted soy flour and lean pork blend of various moisture contents extruded in a single-screw extruder and the sensory texture property of extruded meat analogs as the first step to develop commercial low-cost meat analogs that not only resemble real meats but have excellent sensory textures. Additional work was also conducted to examine the effect of moisture content of soy flour under the extrusion condition (high temperature and pressure) on the fiber structure and overall texturization of the extrudate as a result of changes in chemical bonds between soy proteins. The mixture of soy meal with ground lean pork showed significant decrease in viscosity as compared with either soy meal or ground meat alone. The best sensory texture was obtained for the pork-soy flour blend with 41. 3% moisture content at screw speed of 180 rpm under the feeding-metering-die temperature setting of 140–170–80C.     

Some functional properties of pea and soy bean protein preparations

The physical and functional properties of pea and soy bean protein concentrates, and soy bean isolate were investigated. Pea protein concentrate had good lipophilic properties. High fat absorption capacity was confirmed by the small cooking weight losses of meat model systems containing oil and lard. Better functional properties of pea and soy bean protein concentrates in these model systems may be due to specific surface structure, which was evident on the SEM microphotographs. The physical and functional properties of pea protein concentrate were similar to the properties of soy bean concentrate.     

黄豆酱油与黑豆酱油抗氧化活性及风味物质的比较

本文研究了相同工艺下,黄豆、黑豆两种蛋白原料制备传统高盐稀态酱油的差异。比较两种酱油基本成分及抗氧化活性的差异,并利用顶空-固相微萃取(HS-SPME)和气相色谱-质谱联用(GC-MS)分析两种酱油挥发性风味物质。结果表明,黑豆酱油总氮、氨基态氮、还原糖等显著高于黄豆酱油(p0.05),黄豆酱油鲜味氨基酸含量更高。黑豆酱油抗氧化活性高于黄豆酱油,相关性分析表明总酚、总黄酮及类黑精是酱油抗氧化活性的重要物质基础。两种酱油挥发性风味物质种类及含量差异显著(p0.05),共鉴定出98种物质,黄豆酱油、黑豆酱油总风味物质种类分别有63种、59种,总峰面积分别为297.6×10~7、213.6×10~7。综合分析表明黄豆酱油醇香突出,黑豆酱油醇、酯及醛酮类主要挥发性成分较均衡,风味协调。     

Tuna Protein Nutritional Quality Changes after Canning

Albacore tuna (Thunnus alalunga) was steamed and canned in soy bean oil and sterilized at 115°C for 55 or 90 min. Proximate composition, total amino acid and available lysine content were determined during different phases of the process. Water and protein were lost in all phases and fat content increased. There was a decrease in available lysine during cooking but no loss in total amino acids. Nutritional evaluation of the protein showed differences in biological value and net protein utilization when the canned tuna was mixed with bread flour.     

Study on the Complementation of Two Proteins of Low Quality: Black Bean (Phaseolus vulgaris) and Sesame (Sesamun incdicum L.).

In order to determine the complementary potential of black bean and sesame proteins, female rats were fed diets with 10% protein from black bean, sesame or combinations of these. Data showed that diets with these proteins combined had better quality than either protein alone. Maximum protein quality was observed when the two protein sources were mixed in a 1:l (w/w) ratio. This mixturn had PER and NPR values 2 and 5 times higher, respectively, than those of the black bean protein alone and 61 and 71% of the values of PER and NPR, respectively, obtained with a casein diet. Also, there was no alteration of serum or liver lipids.     

Low carbohydrates bread: Formulation,processing and sensory quality

A low carbohydrate bread formula was prepared using hard red spring wheat flour, soy protein and vital gluten. Soy protein was treated with ethanol and jet-cooked to remove the beany taste. Vital gluten and soy protein blends were prepared and added to the control flour in order to reduce the final starch content by 52%. The ratio of soy protein:vital gluten was adjusted, based on the Farinograph profile of the blend relative to the control flour. AACC Method 10-09, Straight dough, was used for the baking. The amounts of shortening and yeast were increased, to improve the dough consistency and to reduce beany taste, respectively. A blend of 70% gluten and 30% soy protein was added to replace 50% of the control flour. This blend gave a loaf value similar to the control. Overall, the loaf was softer, darker in colour and the grain was more open than the control. Another blend, with 50% soy nuggets and 50% vital gluten, was added to replace 50% of the control flour. This produced a loaf with 35% less volume, darker colour, and a grain similar to the control. The protein content of the final product was 56%, which is much higher than that reported in the literature. Bread with high protein content is more suitable for use in low carbohydrate diets than bread formulations currently used.     

大豆蛋白源配料特性对素肉饼品质的影响

主要研究了大豆拉丝蛋白和大豆分离蛋白(Soy protein isolate,SPI)2种大豆蛋白源配料的功能特性对素肉饼品质的影响.研究表明,大豆拉丝蛋白的蛋白含量越高,素肉饼的品质越高,主要表现在口感韧性强、弹性高,更接近肉的纤维状质构和口感;而在素肉饼配方一定的情况下,大豆分离蛋白的凝胶值对素肉饼的品质影响呈现先...     

Isolation and study of the functional properties of pea proteins.

Proteins of pea seeds were isolated after defatting with hexane using alkaline (0.1 M sodium hydroxide) extraction and acid (HCl) precipitation. Concentrates were also prepared by hexane extraction and ethanolic extraction (pH = 5). Gross chemical composition amino acid content and functional properties (solubility profile, emulsifying--and foaming properties, water--and oil absorption) were studied. The results were compared with the same parameters of soy and lupin protein products. Although the majority of functional characteristics of isolates were lower in comparison to soy isolates, pea protein concentrate and isolate could be successfully used in bakery products for enrichment in protein and improvement of biological value. Their utilization as meat protein substitute in some Frankfurter type sausages is also possibly.     

An enzyme-based extraction process for the purification and enrichment of vegetable proteins to be applied in bakery products

In the current study an efficient aqueous extraction procedure using glucoamylase was developed to produce food grade protein extracts from lentils and white beans. The extracts contained 50.3 ± 0.6 and 49.2 ± 0.05 g protein per 100 g dry extract, respectively. The nutritional value of lentil and white bean protein extracts proved to be satisfying according to the amino acid composition, where methionine was the limiting amino acid. The produced extracts were tested for their technological properties. Both lentil and white bean protein extracts showed similar or even better technological properties regarding foaming and emulsifying capacities, heat stability and gelling properties compared to soy and pea protein extracts. Food application tests in white bread, pound cake and sponge cake proved lentil and white bean protein extracts to be potential alternatives to soy protein in replacing proteins from animal origin.     

坛子肉中氨基酸和脂肪酸营养品质评价

目的评价坛子肉中氨基酸和脂肪酸的营养品质。方法运用多种方法对坛子肉中氨基酸和脂肪酸的组成及含量进行测定,并用必需氨基酸指数法(essential amino acid index method,EAAI)、氨基酸评分法(amino acid score, AAS)、化学评分法(chemical score, CS)评价坛子肉中蛋白质的营养价值。结果坛子肉中氨基酸总量为20.76%±0.21%, 8种必需氨基酸占氨基酸总量的42.60%, 4种鲜味氨基酸占氨基酸总量的36.90%,AAS和CS均表明第一限制性氨基酸为色氨酸。坛子肉中粗脂肪含量为28.15%±0.31%,不饱和脂肪酸占脂肪酸总量的70.79%±0.31%。必需氨基酸占氨基酸总量的38.15%,必需氨基酸与非必需氨基酸的比值为61.68%。结论坛子肉是一种具有独特风味的优质蛋白源以及具有均衡脂肪酸的高营养价值的肉制品。     

Isolation and study of the functional properties of pea proteins

Proteins of pea seeds were isolated after defatting with hexane using alkaline (0.1 M sodium hydroxide) extraction and acid (HCl) precipitation. Concentrates were also prepared by hexane extraction and ethanolic extraction (pH = 5). Gross chemical composition amino acid content and functional properties (solubility profile, emulsifying – and foaming properties, water – and oil absorption) were studied. The results were compared with the same parameters of soy and lupin protein products. Although the majority of functional characteristics of isolates were lower in comparison to soy isolates, pea protein concentrate and isolate could be successfully used in bakery products for enrichment in protein and improvement of biological value. Their utilization as meat protein substitute in some Frankfurter type sausages is also possibly.     

对蛇肉及其有限酶解液营养价值的研究

蛇肉是一种珍贵的传统保健食品资源,含有丰富的蛋白质、维生素(VA,VE,VB1,VB2)、矿物元素(Ca、Zn、Fe、P、Mg、Mn、Ccu)和人体必需氨基酸,其营养价值高于牛肉、鸡肉、鱼肉等肉制品;22.3%水解度的蛇肉酶解液含有蛇肉的全部营养素(蛋白质除外)种类,其营养价值明显优于牛奶、豆浆,甚至优于豆腐脑;该有限酶解液还含有平均分子量为538Da的低肽分子近3%(这占酶解液总氨基酸含量的56.3%),这说明蛇肉蛋白的这种有限酶解物是一种低肽含量占优势的低肽/游离氨基酸混合物。根据现代低肽吸收理论,它比原料蛇肉更易消化吸收,因而更有营养价值和保健功能。     

Development and application of a selective detection method for genetically modified soy and soy-derived products.

A method has been developed to distinguish between traditional soy beans and transgenic Roundup Ready soy beans, i.e. the glyphosate ('Roundup') resistant soy bean variety developed by Monsanto Company. Glyphosate resistance results from the incorporation of an Agrobacterium-derived 5-enol-pyruvyl-shikimate-3-phosphatesynthase (EPSPS) gene. The detection method developed is based on a nested Polymerase Chain Reaction (PCR) procedure. Ten femtograms of soy bean DNA can be detected, while, starting from whole soy beans, Roundup Ready DNA can be detected at a level of 1 Roundup Ready soy bean in 5000 non-GM soy beans (0.02% Roundup Ready soy bean). The method has been applied to samples of soy bean, soy-meal pellets and soy bean flour, as well as a number of processed complex products such as infant formula based on soy, tofu, tempeh, soy-based desserts, bakery products and complex meat and meat-replacing products. The results obtained are discussed with respect to practical application of the detection method developed.     

Biological value of proteins in combined meat paste products

The amino acid composition was studied in certain samples of paste products containing varying ratios of soybean, milk and blood plasma, and whole blood of slaughtered cattle instead of meat and liver proteins. A relationship was established between the degrees of protein amino acid composition balance in these combined products and their biological value. The results of the assay of the protein and urea content and some blood enzymes activity (except alkaline phosphatase) evidenced no significant changes in these parameters depending on the amino acid composition of proteins in the products studied.     

Detection of casein, soy proteins and coagulated egg-white in meat products by electrophoresis on cellulose acetate membranes

Summary A rapid method has been developed for the detection of casein, soy protein and coagulated egg-white in meat products. Fat and serum proteins are removed by hot water extraction. Casein and soy proteins are extracted with 8 M urea. Coagulated egg-white is subsequently extracted with a fresh mixture of 8 M urea/0.15 M thioglycol (9:1). The proteins are precipitated with an acetate buffer of pH 4.6 which is added in 4-fold excess to the urea extract. After isolation and washing of the precipitate the proteins are dissolved in urea or urea/thioglycol and subjected to electrophoresis on cellulose acetate membranes in a suitable buffer system, viz. barbitone/urea pH 8.5 for casein and formic acid/urea pH 4.0 for soy proteins e.q. egg-white. About 0.1% of casein, soy protein and 0.5% of egg-white added to meat products can be detected.

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Zusammenfassung Es wurde eine schnelle Methode zum Nachweis von Casein, Soja-Protein und coaguliertem Eiklar in Fleischerzeugnissen (Bratwurst usw.) entwickelt. Fett und Serumproteine werden mit heißem Wasser extrahiert; Casein und Soja-proteine mit einer 8m-Harnstoff-Lösung. Coaguliertes Eiklar wird dann mit einer frisch hergestellten Lösung von 8m-Harnstoff und 0,15 m-Thioglycol (9:1) extrahiert. Die Proteine werden mit einer Acetat-Puffer-Lösung von pH 4,6 in 4fachem Überschuß präzipitiert. Nach Isolierung und Waschung des Präcipitats werden die Proteine wieder in Harnstoff oder Harnstoff/Thioglycol gelöst und der Elektrophorese auf Celluloseacetat-Membranfiltern in einem geeigneten Puffersystem unterworfen, d. h. Barbitone/Harnstoff pH 8,5 für Casein und Ameisensäure/Harnstoff pH 4,0 für Soja-proteine und Eiklar. Die untere Nachweißgrenze liegt bei 0,1% für Casein und Soja-Proteine und bei 0,5% für Eiklar.

     

Characteristics of the nitrous substances in the meat of sharks and rays as a protein food raw material]

The nitrous composition of meat in 19 species of oceanic sharks and 2 species of rays were analyzed. The meat of these fish species was found to be characterized by a comparatively low protein content, whose amino acids composition proved relatively poor of essential amino acids. The meat of sharks and rays is distinguished by a high level of extractives, whose bulk includes urea and trimethylaminoxide.